Renewable inclosed electric fuse



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Patentes July 21, 192e.

UNITED STATES JOSEPH SACHS, OF HARTFORD, CONNECTICUT.

BENEWABLE INCLOSED ELECTRIC FUSE.

Application led February 19, 1925. Serial No. 10,308.

This invention relates to the class of inclosed electric fuses of the knife blade type which are constructed in such manner that the permanent parts may be readily disassembled when the fusible link is disrupted' and reassembled with a new link connected between the knife blade terminals.

-The object ofthe invention is to simplify and cheapen the construction of such fuses and arrange the elements in a manner that will permit them to be easily manipulated for the renewal of the links, and yet ensure eiicient electrical contacts.

This object is attained by providing the ends of the insulating tubular case with exteriorly threaded Vmetallic bushings against one of which a closure permanently secured to one terminal blade is clamped by a ferrule screwed upon the bushing at that end, and against the other of which a. slotted closure removably attached to the other terminal blade is clamped by a ferrule screwed upon the bushing at that other end, said closures being so engaged with the blade and bushings that they lock the blades in alignment against longitudinal movement and prevent them from turning, when the parts are assembled and the ferrules are bushings to secure the parts together.

secured in place.

In the accompanying drawings Fig. 1 shows aside view of a fuse embodying the invention. Fig. 2 is a central longitudinal section ofthe same. Fig. 3 is a transverse section on the plane indicated by the dotted line 3-3 on Fig. 2. Fig. 4 is a view of one form of the removable closure lor locking plate. Fig. 5 is a section of one of the ferrules. Fi 6 is an end view of one of the ferrules. ig. 7 is a longitudinal section of one of the bushings. Fig. 8 is an edge view of the locking plate shown in Fig. 4. Fig. 9 isl a face view of another design of locking p ate.

The case l is an insulating tube of approved length and diameter., Into each end of the case a metallic bushing 2 is inserted. rlhe bushings may be threaded into the case and rivets 3 driven through the case and The outwardly extending ends of the bushings are exteriorly threaded.

The knife blade terminals 4 have the usual outside contact sections and inside sections to which the ends of the fusible link 5 are detachably fastened, preferably by screws 6. Permanently fastened to the inwardly eX- tending sect-ionv of each knife blade is a vwasher 7 of a diameter which is slightly'less than the diameter of the opening through the bushings, in the outer ends of which the Washers freely fit for the purpose of loosely closing the openings and centering the knife blades when the parts are assembled.

Permanently attached to the knife blade at one end, adjacent to and outside of the Washer 7, is a locking plate 8`which is of such size that it rests against the end of the metallic bushing at that end of the case. Near one edge on the inside, this plate has a stud 9 that projects into a notch 25 in the end of the bushing. This holds the plate from rotating when the parts are assembled, and consequently keeps the blade from turning.

Loosely applied to the knife blade at the other end adjacent to and outside of the washer 7 is a plate 10 which, when the parts are assembled, locks the blade against rotative and longitudinal movements. The edges of the knife blade just outside of the fixed washer 7 have notches 15. This loose locking plate has a slot 11 with one edge 13 designed to be parallel to the plane of the knife blade and the opposite edge 12 oblique with relation to the. plane of the knife blade. The section of the slot which is diametrical and designed to receive the blade is of a length equal tothe width of the blade between the notches, while the section of the slot which is oblique is of a length equal to the widest part of the blade. The slot, which is thus wider at one end than at the other, may be open through the ed e of the plate, as illustrated in Fig. 4, or r the larger size of fuses it may be closed, as shown in Fig. 9. The loose locking plate, if the slot is open, may be thrust edgewise upon the blade opposite the notches or if the slot is closed pushed lengthwise on ythe blade up to the notches, and then given a slight rotative turn so that the section 14 at the ends of the lshort section of the slot, which is then parallel with the sides of the blade will enter the notches and lock the bladefrom endwise movement. This loose locking plate on the inside opposite the narrow end of the slot has a stud 16 that extends into a notch 24 in the end of the bushing. This stud forms a pivot for the oscillatory or swinging movement of the plate, and also holds the plate so that the blade cannot turn when locked in position and all of the elements are assembled. The locking plates at each end are desirably provided on their outer faces with transversely extending grooves 23 adapted to provide passages for the gas generated when the link is fused.

Screwed upon each bushing is a ferrule i7. Each of these fel-rules has an inwardly extending flange iti. On the inside of this flange is a washer 19 and on the outside a washer. 20. 'lhe outer washer is preferably much thinner than the inner washer. These washers, the edges of which span the flange in theferrrule, are fastened together by rivets 21 so that while they are free to rotate they cannot be withdrawn from the ferrule. The washers have slots 22 of a size and shape to fit the knife blades.

In assembling these devices the knife blade designed to receive the loose locking plate and connected by a fusible link to the blade with the fixed locking plate, is thrust through the tubular insulating case and metallic bushings until the fixed plate abuts against one of the bushings. A l'errule is then placed over the blade at this end and screwed u) so as to tightly clamp the fixed plate against the end of the bushing. At the other end the loose locking plate is slipped upon the knife blade and then turned slightly until the metal of the plates at the ends of the shorter section of the slot enters the notches in the blade, after which the other ferrule isslipped over this blade and screwed up so as to tightly clamp the locking plate between the washers in the end of the ferrule and the end of the bushing. To disassemble the parts the ferrules are unscrewed, the loose locking plate is given a slight turn and withdrawn from place and then thev blades and link are free to be drawn out of the tube.

With this construction there are but few loose permanent elements, these being the ferrules and single loose locking plate.

hen the parts are put together the case is closed at one end by the fixed washer, fixed locking plate and the ferrule, and at the other end the case is closed by the fixed washer, loose locking plate and ferrule, which elements co-operate in such manner as to permit the necessary escape of gas but prevent the direct outblast of Haine when a fusible link is blown. i

The locking plates with their studs engaging the bushings keep the blades in alignment and prevent them from turning as well as holding them from endwise movement. lVhen 4a fusible link is blown the gas generated passes out around the edges of the fixed washers on the blades, and edges of the locking plates, then through the grooves in the locking plates to the chamber betweenthe ferrule washers, where it is to weaves an extentcondensed, so the nal expulsion of gas from the ends of the ferrules is effected without dangerous results.

rlhe invention claimed is l. inclosed fuse of the knife blade renew-able type having an insulating case, metallic bushings in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closure on each blade engaged with the end of the bushing at each end of the case, one of said closures coniprising a single piece plate having a slot with a portion as long as the width of'a blade and a portion that is shorter, said plate at the ends of the shorter-portion of the slot being adapted by oscillatory movements to be engaged with and disengaged from notches in the edges of the blade upon lwhich it is loosely placed, and conducting i'errules screwed upon the bushings at each end and clamping the closures between the ends of the bushings and the heads of the ferrules.

2. An inclosed fuse of the knife blade renewable type having an insulating case, metallic bushings in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conduct-ing closure on each blade engaged with the end of the bushing at each end of the case, one of said closures being fixed to one of said blades and the other of saidclosures comprising a single piece plate having a slot with a portion as long as the width of a blade and a portion that is shorter, said plate at the ends of the shorter portion of the slot being adapted by oscillatory movements to be engaged with and disengaged from notches in the edges of the blade upon which it is loosely placed, and conducting ferrules screwed upon the bushings at each end and clamping the closures between theends of the bushings and the heads of the ferrules.

3. An inclosed fuse of the knife blade renewable type having metallic bushings in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closure on each blade engaged with the end of the bushing at each end of the ease, one of said closures comprising a single piece plate having a slot with a. portion as long as the width of the blade and a portion that is shorter, said plate at the ends of the shorter portions of the slot being adapted by oscillatory movements to be engaged with and disengaged from notches in the edges of the blade upon which it is loosely placed and conducting ferrules screwed upon the bushings at each end and clamping the closures between the ends of, the bushings and the ferrules, said ferrules having interior flanges and connected washers, one inside and one outside of said anges, loosely retained in place by the anges.

4. An inclosed fuse of the knife blade renewable type having an insulating case, metallic bushings in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closure on each blade engaged with t'he end of the bushing at each end of the case, one of said lclosures comprising a single piece plate having a slot that is somewhat wider than the thickness of the blade, with an opening from the slot to the edge of t'he plate, sa1d plate at the endsl of the slot being adapted by oscillatory movements to be engaged with and disengaged from notches in the edges of the blade upon which it is loosely placed, and con-l ducting ferrules screwed upon the bushings at each end and clamping the closures between the ends of the bushings and the heads of the ferrules.

5. An inclosed fuse of the knife blade renewable type having an insulated case, metallic bushings inserted in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closure on each blade engaged with the end'of the bushing at each end of the case, one of said closures being fixed to one blade and engaging the bushing so as to prevent rotation of the blade, and the other of said closures comprising a single piece plate having 'a slot that is somevfhat wider than the thickness of the blade, said plate at the ends of the slot being adapted by oscillatory movements to be engaged with and disengaged from notches in the edges of the blade upon which it is loosely placed, means engaging between said closures and the bushingsl to prevent rotative movements of t'he blades, and conducting ferrules screwed upon the bushings at each end and clamping the closures between the ends of the bushings and the heads of the ferrules.

6. An inclosed fuse of the knife blade renewable type havin metallic bushin in serted in the ends o the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closurer on each blade engaged with the end of the bushing at each end of the case, one df said closures comprising a single piece-plate loosely fitted upon a blade and by oscillatory movements being adapted to lock and release the blade both rotatively and longitudinally, and conducting ferrules screwed upon the bushings at each end and clamping the closures between the ends of the bushings and the`heads of the ferrules;

7, An inclosed fuse of the knife blade renewable type having aninsulating case, metallic bushings in the ends of the case, knife terminals extending into the bushings,

a fusible link connectin said blades, a conductin closure on eachgblade engaged with the en of the bushing at each end of the case, one of said closures comprising a single piece platehaving a slot' that is somewhat wider than the thickness of the blade and has a section that is as long as the maximum width of the blade'v and a section that is ofl less length than the maximum width of the blade, the ends of the shorter section of the slot being adapted by oscillatory movements of the plate to be engaged with and disen aged from notches in the edges of the bla e upon which it is loosely placed, and conducting ferrules screwed upon the bushings at each end and clamping the closures between the 4ends of the bushings and the heads vof the ferrules.

8. An inclosed fuse of the knife blade renewable type having an insulating case, metallic bushings inserted in the ends of the case knife blade terminals extending into the ushings, a fusible link connecting said blades, a conducting closure on each blade engaged with the end of the bushing at each en of the case, one of said closures being xed to one blade and engaging ythe bushing in the bushing to prevent movement of theblade when the parts are assembled, said plate being pivotally held by said stud and movable into and out of locking enga ement with the knife blade upon which it is oosely placed, and conducting ferrules screwed upon the bushings at each end and clamping the closures Abetween the ends of the bushings and the heads of the ferrules.

9. An inclosed fuse of the knife blade renewable type havin an insulating case, metallic bushings in 51e ends of' the case, knife blade terminals extending into the bushings, a, fusible link connecting said blades, a centering washer fixed to each blade and loosely fitting within the bushings, a conducting closure on each blade outside of the fixed washer engaged with the end of the bushing at each end of the case, one of said closures comprising a single,l piece plate having a slot, said plate at the ends of the slot being adapted by sidewise movements of the plate to be engaged with and disengaged from notches in the edges of the blade upon which it is loosely placed, and conducting ferrules screwed upon the bushings at each end and clamping the closures between the ends of the bushings and the ends of the ferrules.

10. An inclosed fuse of the knife blade renewable ty having an insulating case, metallic bushin s secured to the ends of the case, knife bla e terminals extending into the bushings, one of said blades being notched outside of 'the end of a bushing, a fusible link connecting said blades, a conducting closure on each blade and engaging with the outer end of each bushing, one of said closures being formed of a single piece of metal and having a slot of varying length, a portion ofthe slot being of suliicient length to receive the Widest part of the blade upon which it is placed and a ortion of a length to t the notched portion of said blade whereby said closure by oscillatory movements may be engaged with and disengaged from the notched section of the blade upon which it is loosely mounted, and conductingV fel-rules screwed upon the bushings at each end and clamping the closures betweenthe ends of the bushings and the ends of the ferrules and holding the elements in interlocked relation.

11. An inclosed fuse of the knife blade renewable type having an insulating case,

metallic bushings in the ends of the case, knife blade terminals extending into the bushings, a fusible link connecting said blades, a conducting closure on each blade engaged with the end of the bushing at each end of the case, one of said closures being formed of a single piece of metal and having a slot of shape and size to permit the blade to be received therein, and said slot permitting anoscillating movement of the closure with relation to the blade on which it is placed whereby after said closure has been placed on the blade against the end of a bushing an oscillatory movement of said closure interlocks the blade With the closure, and conducting ferrules screwed upon the bushings at each end and clamping the closures between the bushings and the ferrules, whereby the blades are firmly held against longitudinal, transverse and rotary movements with relation to the case.

JOSEPH sAoHs. 

